DISTRACTOR HAVING AN INTERNAL LOAD MEASURMENT SYSTEM FOR THE MUSCULAR-SKELETAL SYSTEM AND METHOD THEREFOR
A distractor suitable for measuring a force, pressure, or load applied by the muscular-skeletal system is disclosed. An insert couples to the distractor. The insert has at least one articular surface allowing movement of the muscular-skeletal system when the distractor is inserted thereto. The insert can be a passive insert having no measurement devices. A sensor array and electronics are housed within the distractor. The distractor can dynamically distract the muscular-skeletal system. A handle of the distractor can be rotated to increase or decrease the spacing between support structures. The measurement system comprises a sensor array and electronic circuitry. In one embodiment, the electronic circuitry is coupled to the sensor array by a unitary circuit board or substrate. The sensors can be integrated into the unitary circuit board. For example, the sensors can comprise elastically compressible capacitors or piezo-resistive devices. The distractor wirelessly couples to a remote system for providing position and magnitude measurement data of the force, pressure, or load being measured.
1 . A distractor system for measuring a force, pressure, or load applied by the muscular-skeletal system comprising:
a first support structure;
a second support structure having at least one alignment feature;
a lift mechanism coupled to the first structure and the second support structure where the lift mechanism is configured to adjustable separate the first and second support structures;
a sensor array overlying the second support structure where the sensor array comprises a plurality of sensors for measuring a force, pressure, or load; and
a third support structure coupled to the sensor array.
2 . The distractor system of claim 1 where the second and third support structures form a housing to isolate the sensor array and the electronic circuitry from an external environment.
3 . The distractor system of claim 2 further including
a load pad overlying each sensor of the sensor array where a compliant surface of the third support structure couples to the load pads; and
electronic circuitry coupled to the sensor array.
4 . The distractor system of claim 3 further including a unitary printed circuit board coupling the electronic circuitry to the sensor array.
5 . The distractor system of claim 4 further including an alignment feature configured to receive and align the sensor array to the compliant surface of the third support structure.
6 . The distractor system of claim 5 where the electronic circuitry further includes a transmitter configured to wirelessly transmit measurement data.
7 . The distractor system of claim 1 further including a handle coupled to the lift mechanism configured to dynamically change a separation the first and second support structures.
8 . The distractor system of claim 1 where the second or third support structures comprise PEEK.
9 . The distractor system of claim 1 further including a remote system configured to receive data from the distractor system.
10 . The distractor system of claim 1 further including a passive insert configured to couple to the third support structure.
11 . A distractor system for measuring a force, pressure, or load applied by the muscular-skeletal system comprising:
a first support structure;
a second support structure;
a lift mechanism coupled to the first structure and the second support structure where the lift mechanism is configured to adjustable separate the first and second support structures;
a sensor array overlying the second support structure;
electronic circuitry coupled to the sensor array; and
a third support structure coupled to the second support structure where the third support structure includes a compliant surface and where the sensor array couples to the compliant surface.
12 . The distractor system of claim 11 where the second and third support structures form a housing to isolate the sensor array and the electronic circuitry from an external environment.
13 . The distractor system of claim 12 further including an insert configured to couple to the third support structure where the insert has an articular surface.
14 . The distractor system of claim 11 further including a unitary circuit board coupling the electronic circuitry to the sensor array.
15 . The distractor system of claim 11 further including a remote system configured to receive force, pressure, or load data from the electronic circuitry where one of the second or third support structures includes a transmissive region.
16 . The distractor system of claim 11 where one of the first, second, or third support structures comprises PEEK.
17 . The distractor of claim 11 where each sensor of the sensor array is aligned to a predetermined location of the compliant surface.
18 . A method of muscular-skeletal distraction comprising the steps of:
distracting the muscular-skeletal system with a distractor having a force, pressure, or load measurement system to a first distraction height;
measuring the force, pressure, or load with at least one capacitive sensor;
transmitting the force, pressure, or load measurement data to a remote system;
changing a distraction height of the distractor to a second distraction height;
measuring the force, pressure, or load at the second distraction height.
19 . The method of claim 18 where the step of measuring comprises:
compressing the at least one capacitive sensor;
coupling a signal to the at least one capacitive sensor where the signal relates to the capacitance of the at least one capacitive sensor;
measuring a time period of the signal; and
converting the time period to the force, pressure, or load measurement.
20 . The method of claim 18 further including the steps of:
adjusting the force, pressure, or load with soft tissue tensioning;
measuring changes in the force, pressure, or load in real-time; and
displaying changes in the force, pressure, or load on the remote system.